In this paper, decision-making related to the ranking of flexibility and performance indicators of the flexible manufacturing system (FMS) are taken. Some flexibility and performance selection attributes are considered related to the objectives. The selection of the right factor in this environment is still a complex issue. This paper presents the application of a MADM approach, i.e., complex proportional assessment (COPRAS) for decision making as the ranking of flexibility and performance indicator of FMS. Two illustrative examples are presented: one for the ranking of the flexibility of FMS and the second one for ranking of the performance indicator of FMS. The results obtained by the COPRAS approach for the ordering of flexibility are differentiated with the outcomes of other researches. The result of COPRAS methodology regarding the flexibility shows that product flexibility has the top flexibility, especially for the new part configuration. Secondly, productivity is the primary factor to boost the performance of FMS. This research has illustrated that the COPRAS methodology is logical and more significant for the selections of alternatives even can handle qualitative data for attributes.